CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Net income	$ 161.8	$ 464.4	$ 603.4	$ 547.0
Other comprehensive (loss) income:
Foreign currency translation loss	(1.0)	(2.1)	(2.8)	(3.7)
Defined benefit pension plan:
Actuarial (loss) gain arising during period, net of tax	(1.2)		5.9	(2.1)
Less: amortization of actuarial gain and prior service cost included in net periodic pension cost, net of tax	0.1	0.1	0.5	0.6
Total defined benefit pension plan, net	(1.1)	0.1	6.4	(1.5)
Other comprehensive (loss) income, net of tax	(2.1)	(2.0)	3.6	(5.2)
Comprehensive income	$ 159.7	$ 462.4	$ 607.0	$ 541.8